FLOTATION RESPONSE PREDICTION FROM INTERFACIAL PROPERTIES

A quantitative relationship between contact angle and flotation response using a fundamental and measurable solution chemistry parameter, the critical micelle concentration, has been formulated. Bubble contact angles were measured for the quartz-alkylamine-water flotation system in which the effects of surfactant concentration, surfactant structure and solution pH on contact angle were determined. The alkylamines studied were n-hexylamine, di-n-hexylamine, n-dodecylamine, di-n-dodecylamine and 1,12-diaminododecane. Peak contact angles were primarily a function of chain length, measured as 50° for the hexylamine system and 86° for the dodecylamine series. The diamine gave a contact angle of 60°. The contact angle was unaffected by solution pH over the range 8-10. The surfactant concentration, Cp, corresponding to the maximum contact angle, decreased with increasing number of hydrocarbon branches and increasing solution pH. Flotation recovery data and critical micelle concentrations were correlated to the contact angle data. The correlation analysis quantitatively indicated that 100% flotation recovery can be obtained at surfactant concentrations between 0.01 (Cp) and the Cp or between 0.01 (c.m.c.) and the c.m.c. for the flotation systems surveyed. This unique relationship between flotation response, micellization and bubble contact angle suggests that solution chemistry near the particle surface and near the bubble surface governs the flotation process and the c.m.c., as a solution chemistry parameter, can be used to predict quantitatively flotation response. © 1990.